Learning Forum

[Martinp5]

Hello Sirs, I am experiencing a big problem in non linear buckling:

When I input the APDL written file as:

/prep7

upgeom, , , ,file,rst

cdwrite,db,file,cdb

I transfer the data to a FE modeler and obtain always a extremely deformed body, so I cant carry on the non linear analysis. 

 

Also, every time I change the Data on the note pad file (INP file) I have error as answer from the program, I attach also:

I am working conscientiously in my FInal Project as mechanical engineer, and my supervisor does not help me nor even answer at all, so whatever help received will be very grateful and included in my report,

Thank you very much before hand

[Sean Harvey]

Hello,

So, the new workflow for this would look like the below.  Run you eignenvalue buckling, but then pass the solution cell to the model cell of a new static structural that is setup for large deflection, etc. for the non-linear buckling.  This passes the deformed model to mechanical as the starting point for the non-linear buckling (stress free.

 

While the upgeom command is historically the way we would solve this, this built in capability is much cleaner.

 

You can also pick the solution cell as shown below, and open the properties in workbench and pick the buckling mode and scale factor.  How much initial perturbation is specified can affect the non-linear buckling results so keep in mind you should use something that is physically appropriate, but can bound the buckling load by varying it as needed.

Regards,

Sean

 

[Martinp5]

Thank you very much! I will try this new method today, but I am afraid that I will have the same problem with the excessively deformation.

With tryal and error method I discovered that with specimens dresigned with the ansys CAD, thats not happen, only happened with Geometries drawn in Autodesk Inventor!!!

Thats quite disgusting.... with geometries drawn in space claim, also looks that work, and obtain reasonable deformation in true scale so, I can apply again the non linear force, buuut, in my university, doesnt work now the SpaceClaim CAD design! thats annoying!

Thank you very much for your help!!!